Tetra In Action - June, 2016

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France: June, 2016 - Effective Operation of the HRSG Course

This seminar is primarily intended for O&M staff at all levels of experience working in combined cycle power plants, but should also be of interest to engineers and managers involved in new project development. The course gives attendees a comprehensive yet in-depth survey of a broad range of topics relating to the design, operation and maintenance of the HRSG and associated steam cycle systems.  Drawing on our field experience working at power plants throughout the world, the objective is to provide attendees with clear instruction on the operator actions and design issues that impact HRSG reliability, efficiency and operating life.

The course syllabus can be found here.

Recent Projects: Site Works Survey SE Asia

TETRA Engineering was engaged by a European client to perform a site works assessment at a Southeast Asian power plant construction site. Work had been delayed for months due to disagreements among two parties involved in the project regarding scope of work, responsibility and scheduling issues.
A Tetra engineer visited the site to meet with key personnel from the parties and to inspect the current state of the works. The results of the survey revealed

  • Lack of communication between both parties
  • Delays caused by one party in part of their scope of activity significantly delayed the other party’s progress in the project, causing a large financial loss and deterioration of equipment due to excessive exposure to elements.
  • Discrepancies in the original scope of work caused added delays in the schedule and increasing the level of discord between the two parties
  • As a “neutral” observer, the Tetra engineer was able to identify contradictions in the respective positions of the parties based on actual observations made on site

Corrosion on incomplete boiler assembly Civil Works

Left: Corrosion Due To Inadequate Preservation; Right: Civil Works


Technical Tidbits from Tetra’s HRSG Inspection Planning Guide

Analysis of deposits found in the HRSG is a common and very useful way for determining what is occurring on both the waterside and gas side.  Waterside deposits found in the drum are analyzed to determine chemical and elemental composition.  The presence of certain elements such as chlorine might indicate that there is or was a problem with contamination of the boiler water.  Analysis of gas side deposits such as those found on the cold end tubes can identify the various compounds present and their disposition in the deposits.  Excessive cold end deposition results when unit design does not match actual fuel characteristics or from mistuned process conditions.  The deposits are often corrosive and can lead to premature tube failures as well as loss HRSG or boiler performance.

If you are interested in the full version of the HRSG Inspection Planning Guide (2nd edition) contact  Christine Vallon (This email address is being protected from spambots. You need JavaScript enabled to view it. )  or Natalie Vasa (This email address is being protected from spambots. You need JavaScript enabled to view it. )

Tetra In Action - May, 2016

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Managing the Power Piping in CCGT Plants

Risk of failure and attendant personnel safety concerns are always present when operating highly-pressurized systems.  Over the years, the occurrence of catastrophic events has driven improvements in construction codes and updated recommendations for O&M practices.  As part of this trend, expanded requirements for operations and maintenance (O&M) were recently added to the ASME Code for Power Piping—ASME B31.1.   The “Chapter VII Operation and Maintenance” was created in 2007 to prescribe guidelines that promoted early failure detection and overall safety. This was a fundamental change to the scope of B31.1, which up until then was strictly a design code; going forward, it now serves a dual purpose…

Read the full story by our colleague Robert Rosario, published in Power Magazine here

Dubai: September, 2016 - Boiler & Steam Cycle Knowledge Workshops

Tetra Engineering announces a series of targeted workshops to provide thermal and process plant O&M engineers, managers and operators with a working knowledge in several aspects of the boiler and steam process technology. Drawing on our field experience working at power and process plants throughout the world, the objective is to provide attendees with clear instruction on the operator actions and design issues that can impact reliability, efficiency and operating life.  The programme comprises a set of focused, half-day training modules intended to leave attendees with a practical working knowledge on these issues.  A number of outside experts will join Tetra's senior staff in delivering the workshops.
The course syllabus can be found here.

Technical Tidbits from the Tetra HRSG Inspection Planning Guide

The inspection of drums is a key element in determining the general condition of the waterside pressure boundary of the HRSG components and the quality of the water treatment program.  They are a “window” on what the inside of the water-filled or steam and water-filled tubes and headers in the various pressure circuits (HP, IP or LP) might look like.  Basic inspection is visual, yet often complemented by UT, and PT/MT examinations.
One of the key items of interest is surface passivation.  The HP drum should typically have a dark grey adherent surface layer, characteristic of magnetite, below the maximum waterline.  Above the maximum water line there may be some light red coloration, indicating a mix of magnetite and hematite.  Yet surface color can deceive,  drums with “abnormal” color may simply reflect a specific water chemistry and process condition history.  The experience of the inspector comes into play in these cases, to decide whether what is observed is indicative of a real problem or simply reflects a harmless difference.

Figure 1 : Senior Engineer Mark Taylor from Tetra’s European office enjoying some quality Steam Drum time during a recent HRSG inspection campaign.

If you are interested in the full version of the HRSG Inspection Planning Guide (2nd edition) contact  Christine Vallon (This email address is being protected from spambots. You need JavaScript enabled to view it. )  or Natalie Vasa (This email address is being protected from spambots. You need JavaScript enabled to view it. )

2016 Training Schedule Announced!

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Tetra Engineering has announced its schedule for HRSG & Combined Cycle training events in 2016.  This year we will be hosting training courses in Utah and Connecticut, USA, as well as in France and a new event in Dubai, UAE.  See our training page for more details.

Low Load Operation at Combined Cycle Plants

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Responding to changes in the market, many combined cycle plants are seizing new opportunities by adapting their operation to run more flexibly and at lower loads than the original design intended.  In a recent article in Power Magazine Tetra Engineers David Moelling, Peter Jackson and James Malloy outline some of the challenges that plants must face to ensure the long-term integrity of the steam cycle. 

Tetra Engineering supports plants across five continents in overcoming the engineering difficulties associated with flexible / low-load operation of HRSGs, Power Piping to the Steam Turbine or host processes, as well as the condenser.  Our services include assessing the performance and degradation impact of flexible service which feeds into setting appropriate inspection intervals for different components and developing the associated inspection plans. 

See this short flyer for more information, or get in touch with your nearest office for details about how we can help you. 


Tetra provides services for Cement Industry Heat Recovery Systems

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Tetra Engineering provides services to assist Cement Plant Owners and Operators in implementing, maintaining and improving all types of Heat Recovery Systems.    Our Heat Recovery Steam Generator and steam cycle services have been applied to Rotary Kiln Waste Heat recovery power generation systems.   Whether addressing problems with fouling, or assessing plant modifications for performance improvements, contact Tetra to reduce your energy costs and increase reliability.


Startup Purge Credit Assessment

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Tetra Engineering will be presenting our technical paper on "Impact of Startup Purge Credit on Combined Cycle Plant Operation" at the ASME Power and Energy Conversion 2015 Conference in San Diego, California, USA on June 30, 2015. It describes the technical basis for purge credit operation and provides an example of the impact on fatigue lifetime in key Heat Recovery Steam Generator components.

See the full program at the ASME website here.

Introducing PipeVue 2.0 KMS

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PipeVue Screenshot

ASME B31.1 places practice requirements on Operators for the maintenance of their Covered Piping Systems (CPSs).  Condition Assessments are required on a regular basis, associated with good record-keeping for traceability.  Over time this generates large volumes of documentation and inspection history data, therefore a coherent solution to knowledge management is needed.

PipeVue 2.0 was developed by Tetra Engineering to store and organize large amounts of inspection data in one network-based solution, easy accessible for both plant operators as well as engineers planning yearly inspections. PipeVue 2.0 has three modules covering:

  • Pipe Hangers & Supports;
  • Flow-accelerated Corrosion inspection data; and
  • Grade 91 Weld inspection data

The software stores hanger/support setting information (hot/cold), inspection notes, photos, NDT data and associated design documentation (PDF drawings & manuals) in a simple and categorized manner, with 3D-visualization of all components.

The user can add new data and save to a networked database, where it will be instantly accessible for other users. The software is available as a deliverable from Piping Inspections, or independently as a Knowledge Management System for Power Piping.  Engineering support from Tetra is available as an option, creating an instant channel between plant personnel and third party engineers.

HRSG Inspections - The Key to Reliability

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At Combined Cycle Power Plants the Heat Recovery Steam Generator (HRSG) is an easily-overlooked, but key component, providing steam to the steam turbine and to attached process steam hosts.  While base-loaded HRSGs tend to be the most reliable - cycled or two-shifted plants suffering from accelerated damage - the importance of allocating sufficient resources to maintenance of the HRSG is often only realised in hindsight. 

Even a simple visual HRSG Inspection during an outage can provide useful information about the how the HRSG is aging and what maintenance should be planned to ensure ongoing reliability.  Many have experienced the sudden drop in reliability that comes when a neglected HRSG begans having tube failures in one area, causing frequent shutdowns that later aggravate other incipient problems that could have been avoided by simple performing a Visual Inspection, and taking remedial action early on. 

Tetra Engineering has been performing HRSG Inspections for over fifteen years - over 500 Inspections to date! - and provides an integrated service that supports Owners and Operators throughout the full HRSG life-cycle.  In addition to the HRSG Inspections we also perform HRSG Condition Assessments, in which we review not only the present condition of the HRSG Unit but also how historical operation has affected its integrity. 

As part of its HRSG Life Management services, Tetra also draws on its unique skill set, including extensive field experience and engineering analysis, to assess the HRSG's susceptibility to certain damage mechanisms (e.g. Fatigue, Creep, FAC, Corrosion) and produced customised HRSG Inspection Plans. Those plans can be used by inspectors and NDT-teams during plant outages to target HRSG Inspections where damage is most likely to be found.

For more information on HRSG Inspections and Inspection Planning, see our Field Services page.

See us PowerGen Middle East!

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Tetra Engineering will have a booth next month at the upcoming PowerGen Middle East in Abu Dhabi on October 12-14. We will present our latest service offerings including Field Services, Engineering Analysis, 3rd Party Engineering, and Training. Come see us at the N21 booth, and enter your business card for your chance to win a Wilesco Steam Engine Generator!

About Us

Established in 1988, Tetra Engineering has more than 25 years experience providing solutions to the power industry. We specialize in solutions for HRSGs, conventional boilers & steam-cycle balance of plant.


Our Locations

Offices in: Connecticut, USA; Nice, France; Dubai, UAE.